Rectifier structure



FQMS l957 .1. w. THORNHILI. Erm. 238,757 RECTIFIER STRUCTURE Filed Aug. 2, 1955 ATTORNEYS e' 'www nited States Patent RECTIFIER STRUCTURE Jay W. Thornhill and Edmond D. Jackson, Dallas, Tex., assignors to Texas Instruments Incorporated, Dallas, Tex., a corporation of Delaware Application August 2, 1955, Serial No. 525,837

Claims. (Cl. 317-234) The present invention relates to a highly improved structure for use as a rectifier.

The thermal operating properties of a rectifier are recognized as being a limiting factor with respect to the current load carrying capacity of a particular unit. If the operating temperature of a unit becomes excessive due to high load currents or high ambient temperatures, there exists the danger that the unit may break down partially or even completely from either the mechanical or electrical stand-point. Accordingly, the problem of heat dissipation is of paramount importance and special provisions must be made to insure adequate heat dissipation at the operational current load. Also, it is quite possible to promote the current carrying capacity of a particular rectifying combination by providing for increased or more eflicient heat dissipation. The desirability of making avail# able an efficient and economical current rectifier which will operate at high current loads is recognized by the art. Unfortunately, however, prior constructions which have been devised for this specific purpose have been subject to numerous disadvantages and especially the inability to dissipate large amounts of heat which are generated incident to the operation of such devices as these at high current loads.

vAccordingly, it is a principal object of the present invention to provide a novel structure for a rectification unit which will `operate efficiently `and economically at high current loads and which will function to dissipate large` amounts of heat expediently.

It is a further object of the present invention to provide .an improved rectifier characterized by a cooling system whereby the unit can be operated at high current loads and when so operated will not be subjected to excessive temperatures which otherwise would cause a breakdown of the unit.

It is a further object of the present invention to provide a rectifier assembly which will be characterized by a rugged, durable construction whereby the assembly will stand up bet-ter in commercial use than assemblies heretofore :advanced for this purpose.

Other and further objects of the present invention will become more fully apparent from the following detailed description when taken in conjunction with the drawings in which:

Figure l is a view in cross section through a rectifier structure according to the present invention;

Figure 2 is a view in perspective of the rectifier of the present invention mounted in a cooling bath; and

Figure 3 is a view in perspective of a bank of rectifying units mounted in a cooling bath.

Referring now to the drawings and in particular tovI Figures l and 2 there will now be described the preferred form of the rectifier assembly of the present invention. As will be evident, the unit is composed of an annular base section 10 which is characterized at its upper end. by a flange 11 the outside surface of which is cut `as a, hexagonal nut. The external surface of the base section l0 below the flange 11 is threaded as indicated at 12. De-

f 2,780,757 ce Patented Feb. s. 1957` fined by the top surface of the flange 11 at its inner periphery is xan annular shoulder 13. Seated on the annular shoulder 13 is an annulus 14 which is preferably made of a material such as Pyrex or other insulating material capable of withstanding relatively large changes is temperature without cracking. The upper and lower peripheral marginal edges of the annulus 14 are coated with a silver paste to form rings 15 and 16 at these points. The annulus 14 is fixed to the flange 11 abutting against shoulder 13 by a solder joint indicated by the numeral 17. As will be evident, the solder 17 physically connects the silver ring 15, which directly abuts against shoulder 13, with the flange 11 and forms a hermetic seal. A cap 18, characterized by a central hole 19 and a depending outer peripheral flange 20, is seated on the top of -the annulus 14 with flange 20 lying outside of annulus 14 in abutting relation therewith. The cap is soldered or otherwise fixed to the annulus 14 as indicated by the solder joint 21 which forms a hermetic seal and which physically connects the depending outer peripheral flange 20 with the ring 16 coated onto the annulus 14. The cap 18 further defines a depending inner peripheral flange 22 which forms a shoulder with the inner surface of cap 18. Seated against the shoulder thus defined is the top of a Sylphon bellows 23 which is closed at its lower end. An annular solder joint 24 which physically connects the Sylphon bellows 23 and the inside surface of cap 18 functions to maintain the top of the bellows 23 against this shoullder and also as a hermetic seal.

Within the bellows 23 is a pool of solder 24 in which is embedded one end of a conducting cable 25. The cable 25 is brought out of the unit through the hole 19 in cap 18 and has its other end fixed to a terminal 26.

The bottom of the base section 10 defines a central hole 27 in which is received a cooling element 28 preferably made of copper, aluminum, brass or other material having a high thermal conductivity. The hole 27 defined by the base section 10 is graduated in character and the top of the cooling element 28 is graduated in :a complementary fashion. The cooling element 23 is soldered to the bottom of the base section 10 as indicated by the numeral 29. For this purpose, it is preferred that a silver solder be used. The outer surface lof cooling element 28 is cut lto define :a series of equally spaced annular cooling fins 30.

Positioned between the bottom of bellows 23 and the top of cooling element 28 is a rectifying unit or assembly. For purposes `of simplicity the rectifying unit is shown merely as a wafer 35. One example of a suitable rectifier unit would be a germanium-indium wafer. It will be appreciated, however, that any rectifier unit can be employed. A layer of solder 36 attaches the top surface of wafer 35 to the bottom of the bellows and a layer of solder 37 attaches the bottom surface of wafer 35 to the top of the cooling element 23. It is possible to use any suitable solder to attach wafer 35. In the case of a rectifier wafer of the alloy junction type it would be necessary to select solder having a melting point lower `than the alloy. Hence a laminated construction is provided with the bellows 23 connected to the top of the laminated construction, to thus provide the requisite freedom of movement of the laminated construction in a vertical sense due to thermal expansion. At the same time, the bottom of the laminated construction is in direct heat exchange relationship with the top surface of cooling element 28 and the bottom of base section 10 so that exceedingly 4good heat dissipation will be obtained.

As will be evident from the construction above described, an annular space 34 is defined between the Sylphon bellows 23 on the one hand and the base section 10 and annulus 14 on the other which is hermetically sealed from the atmosphere. This annular space 34 is comwww pletely sealed from the atmosphere and is preferablyl filled withnaniiierht ga'siichsiiiirgenw' liefliif wA'cc'rd ingly, the rectifying elements of the assembly will be sealed ,fi'pni th? imqplggre and will .fungtion solely the iaeltmedium ailing spacepag.

"The'unit as descrihedis. ounted entoa tanlr l0 which has" a lnrad'edepenrng fiairSnppei-@urrage rar para g f'. .Sfliifg' -ihemit against fiuidlakg', alead- ,ga et 36 .underiiespthe'angei '11, which plrenyifdesV a lg'ooll ele`trical'centaet ,as well.i The tanklf'l is*''nrot/'ided"s ,iy i inlet pipe f lliandvan outlet'pipelZ whereby a cooling Afediutn; a$`fr example water, can be circulated through the ank, in heat erich'alnge relationship with 'the 99 re atio ith the"eool'ing`fris'1l`. frteniirifal v,tinted "A etankQ an functions as thecfathogde connection fr'the rectifier unitf lmal 26 "in the circum- Slfllflesof theinventionfunctions'asthe anode c o'rrnec-` tion frwthe vrectifier* i it.' ,It vitis desired, thewafer can be' inverted whereby terminal 44becomes' the anode and terminall :the cathode' Inil'iigure 3,*fthereiis s hown an arrangement for monntf ing a' lpluralityof rectifying units in"'a"conimon"t ank. Each of the rectifying units is of identical construction as sh'onnin Figure 1, and the tank Stidefinesl athi'eaded opening lfor each of vthe rectifier'unitg'in this case three. An inlet pipe 51 is provided lto introduce cooling fiuid such as water into they tank 5f) andA an outlet .pipe 5,2 is provided for the cooling'iiuid toiiow from tanlg 59.' ln .the arrangement shownin Figure .3., .the .anode terrninl 26 rnaydconveniently be Vfined -to a buslbfar which will function as the anode for "all the rectiifying' units anda terminal `53 is ,fixed to tankA :50"to serie the cathode eonnfection. In -these circumstances, therectifier units vwill` be mounted in parallel whereby their current outputs will be additive. lf it is desired, theA Wafer in each unit can be inverted whereby the terminals 26 become cathodes and the terminals 53 the anode.

Ithas been found that a rectifier unit, constructed accoi-ding to the principles of the present invention, when operated is capable of carrying a current load of 100 amp, or more while dissipating efficiently heat generated incident to operation. Thus, the construction is fully capable of operating at high current loads without the danger of `becoming overheated.

Although 4the present invention has been shown and deseribedin terms of a single 'preferredembodimenn nevertheless, various changes and inodificationsfsuch as are obvious to one skilled in the art, are deemed rto be within the spirit, scope and contemplation of the present invention. A YWliatis claimed is:

1.*"A r'lecftiiier structure comprising a*v rectifier unit,y an

element 2S and more specifically'mlieat ,eric

4 annular resilient member attached to the top of said unit, "ln'g"leiiirit' rattaeheii to" tl'ie vbritt-oni of said4 unit; means surrounding said and said annular resilient member and defining therewith a hermetically sealed annular space, and said means defining threads on its outer surface whereby said structure can be readily mounted and removed from a container having a threaded opening.

2. A rectifierstructure as defined in claim 1 wherein said cooling element is characterized bya series of cooling fins.

3. A rectifier structure as defined in claim 1 wherein said annular resilient member is characterized as a Sylphon bsllowsf 4. viectiiier structure as defined in claim 1 wherein said means further defines a nut on its outer surface.

5. A rectifier structure comprising a rectifier unit, an annular resilient member attached to the top of said unit, a coglflg element attached to the `bottomet .said unit, means"surroun7ding said unit 4and saidannul'ar resilient member and defining therewith a hermetically, sealed annular'spaee'saidmeans defining threads on 'its outer surfare; a Cntaner defining threaded opening in ifs. tcp id harina 'an inlet arid an Outlet, and. said means' being threaded into the opening in said container with said eenling'y *elternent projecting inside of said container.

' d rec fier str1. i titreI as defined in claimAS wherein said coo/ling ement defines av series of cooling fins.

7 geef r structure as defined in claim 5 wherein said annulairesilient member is characterized as a Sylphon, bellows. i

A rectifier amature. as @mined in Claim. 5. wherein, said further-.defines a nut onits o uter's'nrfaceabove saidl threads.

"9L, A reqter maar@ as defined.- in daiml 8 wherein a saslrt iQSitiOnel between said. but and Said meiner- 10. A rectifier structurel comprising a container having a plurality of threaded openingsI in its top surface and an inlet and outlet and a rectifier assembly threaded into each said threaded opening, each saidassembly comprising a rectifier unit, an annular resilient member attached tov the top of said unit, a cooling element attached to the bottom of said unit, and means surrounding said unit and. Seid annular resilient member and defining therewith. afherrnetically sealed annular space, said means defining threads' mit# Outer Surface- Referlences Cited in the file of this patent UNITED STATES PATENTS 1,799,854 Levy Apr` 7*, 1931- 25,383,735 Ray, Aug. 28, 19.45 23712555505V Websteretal Nov. 29, 1-955 2,734,154 Pankove Feb. 7, 195.6.

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